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[libromdata] ISO: Always use host-endian except for CD-i, in which case, always use big-endian.

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Checking for 0 wastes time, since standard ISO-9660 always has both
versions filled in, whereas CD-i is big-endian only. The fields were
likely kept as-is to make it easier to write tools to handle CD-i
format, since it can use existing code on big-endian platforms.
This commit is contained in:
David Korth 2021-04-17 21:45:06 -04:00
parent f53eff8bf6
commit 5cfce44312
2 changed files with 24 additions and 30 deletions
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28
src/libromdata/Other/ISO.cpp
View File

@ -145,6 +145,26 @@ class ISOPrivate final : public RomDataPrivate
{
return static_cast<DiscType>(ISO::checkPVD(pvd.data));
}
/**
* Get the host-endian version of an LSB/MSB 16-bit value.
* @param lm16 LSB/MSB 16-bit value.
* @return Host-endian value.
*/
inline uint16_t host16(const uint16_lsb_msb_t &lm16)
{
return (likely(discType != DiscType::CDi) ? lm16.he : be16_to_cpu(lm16.be));
}
/**
* Get the host-endian version of an LSB/MSB 32-bit value.
* @param lm32 LSB/MSB 32-bit value.
* @return Host-endian value.
*/
inline uint32_t host32(const uint32_lsb_msb_t &lm32)
{
return (likely(discType != DiscType::CDi) ? lm32.he : be16_to_cpu(lm32.be));
}
};
/** ISOPrivate **/
@ -271,14 +291,14 @@ void ISOPrivate::addPVDCommon(const T *pvd)
// Size of volume
fields->addField_string(C_("ISO", "Volume Size"),
formatFileSize(
static_cast<off64_t>(host32ifNZ(&pvd->volume_space_size)) *
static_cast<off64_t>(host16ifNZ(&pvd->logical_block_size))));
static_cast<off64_t>(host32(pvd->volume_space_size)) *
static_cast<off64_t>(host16(pvd->logical_block_size))));
// TODO: Show block size?
// Disc number
const uint16_t volume_seq_number = host16ifNZ(&pvd->volume_seq_number);
const uint16_t volume_set_size = host16ifNZ(&pvd->volume_set_size);
const uint16_t volume_seq_number = host16(pvd->volume_seq_number);
const uint16_t volume_set_size = host16(pvd->volume_set_size);
if (volume_seq_number != 0 && volume_set_size > 1) {
const char *const disc_number_title = C_("RomData", "Disc #");
fields->addField_string(disc_number_title,

26
src/libromdata/iso_structs.h
View File

@ -81,32 +81,6 @@ typedef union _uint32_lsb_msb_t {
} uint32_lsb_msb_t;
ASSERT_STRUCT(uint32_lsb_msb_t, 8);
/**
* Get the host-endian 16-bit value if it's non-zero.
* Otherwise, get the swap-endian 16-bit value.
*/
static inline uint16_t host16ifNZ(const uint16_lsb_msb_t *lm16)
{
uint16_t val = lm16->he;
if (val == 0) {
val = __swab16(lm16->se);
}
return val;
}
/**
* Get the host-endian 32-bit value if it's non-zero.
* Otherwise, get the swap-endian 32-bit value.
*/
static inline uint32_t host32ifNZ(const uint32_lsb_msb_t *lm32)
{
uint32_t val = lm32->he;
if (val == 0) {
val = __swab32(lm32->se);
}
return val;
}
/**
* ISO-9660 Primary Volume Descriptor date/time struct.
* Note that the fields are all strings.